First in a trio of translated books about classic Greek figures, Prince Orpheus by Paule du Bouchet, illus. by Fabian Negrin, retells the legends of the Greek musician, including his rescue of Eurydice from Hades (given a happy ending here). In Diogenes' Lantern by Fran oise Kerisel, illus. by Fr d rick Mansot, tales of the philosopher are related (though the translation may require some decoding by adults). Readers learn that The Perfect Knight does not exist in the book by Catherine Gousseff, illus. by Fabian Negrin. Peace, not war, is the ideal, according to the damsel who questions the knight about his quest for perfection. Painterly illustrations face each page of text in the elegantly laid out, hand-sized, paper-over-board books. (Mar.)